1. Field of the Invention
The present invention relates to an electric bicycle motor power control apparatus, and more particularly to the electric bicycle motor power control apparatus capable of effectively minimizing a change of motor periodical outputs while pedaling the bicycle and providing a mild and consistent motor output to the bicycle.
2. Description of the Related Art
The magnitude of a motor output of a conventional electric bicycle is mainly determined and controlled by the following two methods:
(1) The motor output is controlled according to the moving speed of pedaling (or a crank).
(2) The motor output is controlled by a pedaling (crank) movement speed. The higher the pedaling movement speed, the faster the assisting force provided by motor. In such control mode, the motor output can be adjusted according to the pedaling speed (wherein the motor output is directly proportional to the pedaling speed) while riding an electric bicycle. However, if the bicycle is climbing a slope, the pedaling speed will be reduced due to the steep slope, and the motor output will be lowered, and thus resulting in the situation that the electric bicycle cannot climb up the slope or move forward.
(3) The motor output is controlled by the pedaling torque. In other words, the motor output is controlled according to the pedaling torque. The larger the pedaling torque, the larger is the motor output. U.S. Pat. No. 7,814,800 applies this control method. In FIG. 1, when a user pedals a pedal, and the crank 1 is moved to the position 0, the torque value is equal to 0; when the crank 1 is moved to the position 90, maximum torque is produced; when the crank 1 is moved to the position 180, the torque value is equal to 0. Therefore, when the pedal is pedaled to the position 360, the relation with torque is shown in FIG. 2, and there is a too-large change of waveforms to cause the motor to produce a too-large change of periodical outputs. In other words, the pedal is moved to the position 360. A different output is produced in a movement period, and thus causing the rider to have an uncomfortable feeling.